The great Peter Needham reveals the names he has used in his (Ancient) Greek translation of Harry Potter and the Philosopher's Stone. My Greek is far too rusty to attempt to read it, so I was interested in the snippets he includes in his article on The Classics Pages."Harry Potter is Ἅρειος Ποτήρ [Hareios Poter]- Aρειος [areios] means "belonging to Ares", the war god - appropriate for the young warrior, and ποτήρ [poter] is a Greek word for "cup" or "goblet" - presumably the cup of wisdom from which Harry must quickly learn to drink deeply." The rendering I find most appealing is that of 'muggles' as "Μύγαλοι [Mugaloi]Greek for field-mice, quite appropriately)."
'Harry Potter in Greek' by Peter Needham. The Classics Pages.